The age-associated reduction in GH secretion is strongly influenced by a decrease in physical fitness. The consensus of available data support the idea that both excessive somatostatin release and diminished GHRH secretion and/or a deficiency of the GHRP receptor ligand are responsible for the decrease in GH secretion in the aging adult. Exercise of appropriate intensity serves as a powerful stimulus for GH secretion. The purpose of this study is to understand the neuroendocrine mechanism driving this response.